1. Field of the Invention
This invention pertains generally to agricultural tool bars.
2. Description of the Prior Art
Due to the need to mount ground working tools or a tool bar that is foldable from an extended, ground working transverse position to a narrow, transport position, it has become commonplace to install the actuating hydraulic cylinders inside the hollow tool bar rather than on the exterior of same to avoid tool conflict. If a tool bar wing is only to be folded upward about a suitable offset hinge to a position 90.degree. to the central tool bar section, the rod of the cylinder can be connected directly to an ear connected to the wing which is located inside the central section when the cylinder is retracted and the wing section is in the working position. However, if it is desired to fold the wing approximately 180.degree., so same lies on top of the center section in the folded position, additional structure is needed. This structure may include an additional pair of links pivotally connected to the end of the cylinder rod and a pair of rollers also similarly connected to the cylinder rod. The other ends of the links are pivotally connected to the ear rigidly connected to the associated wing. An additional fulcrum, generally adjacent the hinge, may be provided for contact by the links when the wing is moving in the inner, overcenter of the hinge pivot position. The rollers generally provide support for the cylinder rod under the wing weight and maintain same and the cylinder in a horizontal position even where the base end of the cylinder is pivotably mounted to the central tool bar section.
The above structure does provide the 180.degree. folding capability desired, but the wing is not well controlled as it moves over the hinge pivot to the folded and unfolded positions. Specifically, the rollers in the past have not been carefully sized to the interior tool bar dimensions and move substantially up and down between the upper and lower walls during the process with attendant wing fall. If the rollers are carefully sized to the interior tool bar dimensions to minimize wing fall they bear too tightly, for example, against the top wall on folding, and the folding cannot be completed. Thus, wing fall is controlled, but the design is not workable.